Background: Cyclotides are biologically active, plant-derived macrocyclic peptides. All cyclotides and their acyclic variants have been isolated from dicots. Results: We characterized nine novel linear cyclotides from monocot plant Panicum laxum. Conclusion: Our study provides the first evidence of linear cyclotides at the protein level in the Poaceae. Significance: Ancient linear cyclotide analogs may have existed before the divergence of dicots and monocots.